Saltwater haven turns to dust as big dry bites hard

By Orietta Guerrera

THE drought has reduced Australia's biggest permanent saltwater lake, Lake Corangamite, to its lowest level in more than 60 years.

Water has receded several hundred metres from its normal shoreline, and sections of the northern end resemble a dust bowl. The southern end is rapidly declining.

Conservationists and locals are worried about the impact of decreasing water levels on native flora and fauna, and the thousands of migratory birds that seek refuge at the internationally recognised Ramsar wetland, feeding on brine shrimp.

Corangamite Catchment Management Authority wetlands co-ordinator Donna Smithyman said with water, which usually cover 23,300 hectares, so far from the normal shoreline it had become difficult to measure its quality, depth and temperature.

Water in the lake, which dominates the landscape between Colac and Camperdown in Victoria's Western District, is usually about four times saltier than seawater. But without regular flows of fresh water it is now believed to be even more concentrated.

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Ms Smithyman said this had the potential to harm insects that lived along the beaches of tiny, delicate coxiella snail that lined the lake.

Foxes were of mounting concern.

While islands in the lake once protected bird colonies which congregated there to breed, plummeting water levels had left wildlife within striking distance of their predators.

"They like the easy option, foxes," Ms Smithyman said.

"If they can get access to chicks and eggs, that's a good option for them. It's hard to document the impact foxes have had, but you know that their access has increased."

In August, with lakes such as South Australia's Lake Eyre bone dry, vast flocks of banded stilts descended on Corangamite.

Many observers are anxiously waiting to see whether these wading birds reappear this winter.

"This has been the worst recorded year for water birds breeding pretty much throughout Australia, but particularly south-eastern Australia," Ms Smithyman said. "I know everyone's looking to see if they come back again. It will depend if there's any water, it might not have to be much."

Native saltmarsh that dominates the lake's banks are holding up despite little rain, but stretches of revegetation have had to be watered by hand.

Windy days have whipped up salt lying on the shore, dumping it on nearby properties and burying new plants.

Greening Australia field officer Ammie Jackson said wandering stock from nearby farms, trampling and feeding on vegetation — which was vital habitat for birds and other animals such as the endangered Corangamite water skink — had become an issue. She was working with landholders to improve fencing.

Lake Eyre is bigger but it is often dry and Lake Corangamite trumps it in the so-called permanent stakes. But it is its permanent status that is in doubt.

The lake, formed by lava flows, was at its highest levels in the late 1950s when, after a series of wet years, it flooded nearby properties. Its normal depth is about four metres.

Long-time local Harvey Eldridge, 75, recalled families flocking to the lake's east shores after they transformed into a makeshift beach. "You could hardly get a parking spot, some nights there, hot nights," he said.

Harvey's son, Frank, whose 130-hectare dairy farm borders the lake, said the only sightseers now came to see how far the lake had receded.

"It will take a succession of really good years to bring it back to anywhere near where it used to be. One or two years would have little effect on it," he said. "But if it's been dried before, something tells me that it could probably fill up again."